The story begins with the mysterious disappearance of private detective Harry Goodman, which is to be investigated by his 21-year-old son Tim. Helping him in the investigation will be his father's former partner, the chatty detective Pikachu, who is a mystery even to himself. Discovering that they are somehow fantastically able to communicate with each other, Tim and Pikachu set out to find clues in the neon-lit streets of Rime City, a modern sprawling metropolis where humans and Pokémon live side by side. The pair encounter a wide variety of Pokémon and uncover a terrible conspiracy that could destroy this peaceful coexistence and become a threat to the entire Pokémon universe.